Third-order nonlinear optics of Na clusters bound to dielectric surfaces

The third-order nonlinear optical response of collective Na ensembles (‘clusters’), bound to mica surfaces, has been studied using cw lasers in a backward-propagating degenerate four-wave-mixing (DFWM) geometry. Large values of χ(3) are found, which are independent of cluster size for a range of cluster size diameters between 60 and 240 Å.